1. Field of the Invention
This invention is directed to a container filling machine and more particularly concerns the drive means for rotary type filling machines such as are used in the brewery and soft drink industries for the high speed, automatic filling of containers, e.g. bottles and cans, with beverage.
2. Description of the Prior Art
Container filling machines of the type with which the present invention is primarily concerned are comprised generally of a stationary base and a filler head mounted in the base for rotary motion about a vertical axis through the center of the head. The head is formed with an upper filler bowl portion containing the liquid which is to be introduced into the containers and equipped with a series of depending filler valve assemblies which serve to control liquid flow into the containers. The containers are supported in the head by a lower filler table or turntable connected to the bowl for rotation therewith as an assembly and provided around its periphery with a series of container support and lift assemblies which serve to receive the incoming containers and to move the same relatively into and out of filling position with respect to the valve assemblies in the course of a container filling cycle.
The containers are normally delivered into the filler head through means of a timing screw and a multiple pocketed rotary member such as a starwheel which co-act to impart a predetermined spacing to the containers such that upon entry to the head the containers are received properly upon the container lift assemblies. An additional multiple-pocketed rotary member, i.e., starwheel, is normally also mounted in the base of the filler to receive the containers from the head at the completion of the filling cycle and to deliver the same directly to a crowner or capper unit in those instances wherein the crowner/capper is formed as an integral part of the filler or to a suitable take-off conveyor where the crowner/capper constitutes a separate, free standing unit.
In the typical such filling machines, the drive system includes a main power source such as a variable speed drive motor mounted in the base of the filler with the drive shaft of the motor extending horizontally in the base and supported in suitable bearings or pillow blocks. The filler table is provided with a large diameter ring gear mounted horizontally of the table in centered relation to the axis of rotation of the head proper. A spur gear which is mounted in the base of the filler in driving engagement with the ring gear is coupled by way of gear reducer and a timing chain-sprocket unit to the motor driveshaft whereby to rotate the head when the drive motor is energized. The mounting shafts of the infeed and discharge starwheels are each normally provided with a ring gear and are coupled to the driveshaft of the motor to rotate in a predetermined timed relation to the head through additional gear reducers and separate timing chain-sprocket units.
In the case of a filler having a crowner or capper unit as an integral part thereof, the drive system usually further includes additional timing chain and sprocket power take-off units coupling the main driveshaft to both the rotary head of the crowner/capper and the crowner/capper discharge starwheel with suitable gears and gear reducer unit being utilized to provide a desired speed correlation between these elements and the filler head and its starwheels.
While this general type of drive arrangement has long been accepted in the industry as standard, there are a number of inherent drawbacks in such a drive. For one thing, the use of multiple component, more or less independent drive trains for the filler head, each of the filler starwheels and the crowner/capper head renders it difficult, even with the exercise of close control over manufacturing tolerances and component specifications, to attain precise timing between the filler head and the feed and discharge starwheels. Moreover, operational wear in, and between, the drive components leads to further problems in maintaining precise control of timing in the filler over extended periods of filler operation. The lack of timing precision in the filler results in a rough or irregular handling of the containers at the container infeed and discharge zones and to lack of exactness in container placement on the container support and lift assemblies. In addition to leading to irregular or unsatisfactory filling of the containers, the lack of correct timing leads to excessive wear in the various container handling parts of the filler and its associated infeed and discharge starwheels. The absence of a smooth passage of the containers into and out of the filler head and the loss of precision in the placement of the containers on the lift assemblies of the filler head is particularly burdensome at the high container handling speeds required in present day fillers and, if not rectified, requisite filler speed and production outputs cannot be maintained. The use of added and dimensionally more exact container handling parts in the container infeed and discharge zones as one measure to attain close control over container movement in the critical areas of the filler has been only partially successful in reducing this problem.
A further drawback of the conventional drive arrangement is lack of ready serviceability, the drive components being relatively inaccessible and difficult to adjust with any degree of precision.
The complexity of the described drive arrangement further adds considerably to the initial cost of the filler and is thus objectionable on this further basis.